Minerals are one of the five fundamental groups of nutrients needed to life. Micronutrient malnutrition affects >50% of the worldwide population. In particular, iron, zinc and calcium are considered an emerging public health problem in most of developing countries. In developed countries there are also serious problems of deficiency of minerals due to improper eating habits that has prevailed the comfort and pleasure to health. Iron deficiency is the most common nutritional problem in the world. As well as affecting a large number of children and women in developing countries, it is the only nutrient deficiency which is also significantly prevalent in industrialized countries. The consequences of iron deficiency anemia are very serious. Anemia resulting from iron deficiency in young children has become very common since the level of bioavailable iron in a typical infant's diet is low while their rapid growth requires a much higher level of iron. The consequences of iron deficiency anemia (IDA) are very serious as it is associated with impaired cognitive and psychomotor development, reduced growth and decreased resistance to infection.
To increase the daily intake of these minerals, numerous food supplements containing different inorganic and organic forms of these metals are commercially available. At any rate, it is quite well known that inorganic salts have a very low bioavailability. Organic salts, commonly based on gluconate, citrate, or other molecules, are characterized by a higher systemic effect. Therapeutic doses of iron supplements, which are prescribed for iron deficiency anemia, may cause gastrointestinal side effects such as nausea, vomiting, constipation, diarrhea, dark colored stools, and/or abdominal distress. Therefore, there is a need of providing new formulations for metal supplementation, in particular for iron supplementation, with minimum gastrointestinal side effects.